Infra-red gas burner structure



Sept. 5, 1967 j J, FANNON JR ET AL 3,339,539

INFRA-RED GAS BURNEIR STRUCTURE 4 Sheets-Sheet 1 Filed Sept. 21. 1964 mg W N \wbx w cw M mm J.M d om v0 \mmwm 0 JJ 1 M ATTORNEYS J. J. FANNON, JR. ET AL 3,339,539

INFRA-RED GAS BURNER STRUCTURE 4 Sheets-Sheet 2 Sept. 5, 1967 Filed Sept. 21. 1964 BY M WWW M ATTORNEYS J. J. FANNON, JR., ET AL 3,339,539 INFRA Sept. 5. 1967 -RED GAS BURNER STRUCTURE 4 Sheets-Sheet 5 Filed Spt. 21. 1964 wmT,

INVENTORS JOHN J. FAN/VON, JR.

and MARC RESEK ATTORNEYS Sept. 5, 1967 J, J. FANNON, JR ET AL 3,339,539

INFRA-RED GAS BURNER STRUCTURE 4 SheetsSheet 4 Filed Sept. 21 1964 INVENTORS JOHN J. FAN/VON, JR.

and MARC RESEK ATTORNEYS United States Patent 3,339,539 lNFRA-RED GAS BURNER STRUCTURE John J. Fannon, Jr., Grosse Pointe Park, Mich., and Marc lgesek, Shaker Heights, Ohio, assignors, by mesne asg lgunments, to Fostoria-Fannon, Inc., a corporation of Filed Sept. 21, 1964, Ser. No. 397,775 11 Claims. (Cl. 126-92) This invention relates to heating apparatus and, more specifically, to novel improved line burners and to combustion type infrared generators employing these burners.

Copending application No. 395,839 filed Sept. 11, 1964, by John J. Fannon, Jr., for Apparatus discloses line burners in which a combustible fuel-air mixture flows from a plenum or distribution tube through an orifice grid and burns on the outer surface of the grid. The heat liberated by the combustion of the fuel-air mixture may be transferred by direct radiation or contact or by circulation of the burning gases, depending on the application of the burner and/or the type of heating device in which it is incorporated. 01' these burners may be readily provided with a radiant grid which is heated to incandescence by the burning gases and emits infrared radiation which is directed onto the articles or into the area to be heated.

These line burners have a number of advantages over prior art burners of the same general type including higher operating temperatures, greater efiiciency, higher heat output per unit of space occupied, and longer useful life. In addition, they are applicable to a Wider variety of processes, usable in more types of heating devices, easier and cheaper to manufacture, install, and service, less subject to distortion induced by expansion and contraction of their components as they heat up and cool off, and are, for all practical purposes, free from flashback.

It is a primary object of this invention to provide novel improved line burners and infrared generators which have all of the just-described advantages of the Fannon type burners and infrared generators disclosed in copending application No. 395,839 and which, in addition, have important advantages over the latter.

In the Fannon type line burners and infrared generators disclosed in the above-mentioned copending application, the fuel-air mixture distribution tube is formed from sheet metal and has open ends which are closed by brazing end members to the tube. Also, in the Fannon type apparatus, mounting members are provided to fix the burner or infrared generator to its supporting structure; and a combustible mixture supply conduit is brazed to the distribution tube or one of its end members to supply combustible mixture to the distribution tube without leakage. Thus, in Fannon line burners and infrared generators, a number of parts and assembly operations are required to provide end closures for the distribution tube, to connect the combustible mixture supply conduit to the tube, and to make provision for attaching the burner or infrared generator to its supporting structure.

We have now discovered that the number of parts of and operations necessary to assemble Fannon type line burners and infrared generators can be materially reduced and the cost of manufacturing them substantially decreased, that the possibility of the combustible mixture leaking from the ends of the distribution tube can be eliminated, and that the burner or infrared generator can be more easily and securely attached to its supporting structure by substituting for the end members and the mounting structure heretofore employed, novel end brackets fixed by angle clamps to the open ends of the distribution tube. These novel end brackets, which are integral parts of simple configuration, form closures for the open ends of the distribution tube and also provide a mounting arrangement by means of which the burners and infrared generators of the present invention may be readily and rigidly connected to their supporting structure.

By employing the novel end brackets just described, the separate components heretofore necessary to attach the burner or infrared generator to its supporting structure are eliminated, the number of steps required to assemble the burner or infrared generator is materially reduced, and, by employing gaskets between the end brackets and the ends of the fuel-air mixture distribution tube, the possibility of the combustible mixture leaking through the ends of the tube and the hazards attendant thereto are eliminated as is the necessity of brazing the combustible mixture supply conduit to the distribution tube.

We have also discovered that further significant reductions in manufacturing costs may be effected by substituting novel U-shaped bolted straps for the brazed-on orifice grid supporting straps disclosed in copending application No.- 395,839. These straps are assembledon studs utilized to support other components at the same time as the latter. Consequently, the use of the orifice grid supporting straps disclosed in this application makes it possible to eliminate a brazing operation without the necessity of using a separate assembly step in its place.

Further manufacturing economies may be effected, in accordance with the principles of the present invention, by substituting a novel unitary grid supporting clip we have invented for the combination of inner and outer grid clips disclosed in the above-mentioned copending application for supporting the radiant grids of Fannon type infrared generators. This improvement reduces the number of components which must be fabricated and assembled; and, consequently, its use makes its possible to manufacture Fannon type infrared generators at a lower cost than heretofore.

Another important improvement We have invented is a unitary combination clip capable of supporting both an orifice grid and a radiant grid. This combination clip may be employed to advantage in the manufacture of Fannon type infrared generators as its use makes it unnecessary to employ separate orifice and radiant grid supporting elements. Consequently, this improvement provides significant reductions in manufacturing costs in that it reduces the number of components to be fabricated and the number of assembly operations.

A further novel and important feature of the present invention is an improved reflector for Fannon type line burners and infrared generators. Our improved reflector is so constructed that combustion products may freely escape through it. This is of material assistance in assuring proper operation under various adverse conditions where entrapment and accumulation of combustion products under the reflector would have a deleterious effect on burner operation.

From the foregoing, it will be apparent that further objects of the present invention reside in the provision of line burners and/ or infrared generators which, in comparison to those heretofore known:

(1) Have fewer components which are easier to assemble and are therefore less expensive to manufacture;

(2) Are easier to attach to their supporting structure;

(3) In conjunction with the foregoing object, have novel end brackets by which the infrared generators may be more securely attached to their mounting structure;

(4) Provide more effective seals at the ends of the fuelair mixture distribution tubes;

(5) Have novel improved reflectors through which combustion products may escape;

(6) Have novel improved unitary clips for supporting radiant grids;

(7) Have novel bolted-on type orifice grid supporting straps; and

(8) Have a novel unitary combination clip for supporting both an orifice grid and a radiant grid.

Additional objects, other advantages, and further novel features of the present invention will become apparent from the appended claims and as the ensuing detailed description and discussion proceeds in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side view of an infrared generator embodying the principles of the present invention and supporting structure therefor with portions of several components being broken away to better show the construction of the infrared generator;

FIGURE 2 is a section through the infrared generator of FIGURE 1, taken substantially along line 22 of the latter figure;

FIGURE 3 is a perspective view of an angle clamp employed in the infrared generator of FIGURE 1 and a portion of the infrared generators fuel-air mixture distribution tube, to which the angle clamp is attached;

FIGURE 4 is a perspective view of a novel end bracket employed in the infrared generator of FIGURE 1;

FIGURE 5 is a side view of a second form of infrared generator constructed in accord with the principles of the present invention and a portion of the infrared generator supporting structure;

FIGURE 6 is a vertical section through a third form of infrared generator constructed in accord with the principles of the present invention and having bolted on type orifice grid supporting straps, one-piece radiant grid supporting clips, and improved reflectors, through which combustion products may escape, the end brackets of this infrared generator being omitted for the sake of clarity;

FIGURE 7 is a perspective view of the radiant grid supporting clip employed in the infrared generator of FIGURE 6;

FIGURE 8 is a side view of the radiant grid supporting clip;

FIGURE 9 is a top view of the radiant grid supporting clip;

FIGURE 10 is a perspective view of the orifice grid supporting strap employed in the infrared generator of FIGURE 6;

FIGURE 11 is a fragmentary view of the infrared generator of FIGURE 6, taken substantially along line 1111 of the latter figure and showing the orifice grid supporting strap assembled to the fuel-air distribution tube of the infrared generator;

FIGURE 12 is a fragmentary view of the infrared generator of FIGURE 6, taken substantially along line 12-12 of the latter figure and showing the relative disposition of a number of the infrared generator components;

FIGURE 13 is a fragmentary view of the infrared generator of FIGURE 6, taken substantially along line 13-13 of the latter figure and further illustrating the nature of the reflectors of the infrared generator;

FIGURE 14 is a longitudinal vertical section through an infrared generator constructed in accord with the principles of the present invention and equipped with orifice grid supporting end brackets and unitary combination clips adapted to support both the orifice grid and the radiant grid of the infrared generator;

FIGURE 15 is a transverse vertical section through the infrared generator of FIGURE 14, taken substantially along line 1515 of the latter figure, with the end bracket and gasket and the reflectors omitted for the sake of clarity;

FIGURE 16 is a view of the infrared generator of FIG- URE 14, taken substantially along line 16-16 of FIG- URE 15 and showing the relative disposition of several of the infrared generator components; and

FIGURE 17 is a side view of the end brackets employed in the infrared generator of FIGURE 14.

Referring now to the drawing, in which exemplary embodiments of the present invention are shown, FIGURE 1 depicts an infrared generator 20 constructed in accordance with the principles of the present invention. Infrared generator 20 includes a fuel-air mixture distribution tube 22; an orifice grid 24, through which the fuel-air mixture flows from the interior of distribution tube 22 to a combustion zone adjacent the outer end or face 26 of the grid; a radiant grid 28, which is heated to incandescence by the combustion of the fuel-air mixture; reflectors 30 for concentrating the radiant energy emitted by radiant grid 28 and projecting it in the desired direction or directions; and novel end brackets 32 and 34 which form closures for the open ends of distribution tube 22 and by which infrared generator 20 is attached to a supporting frame 35 shown diagrammatically in FIGURE 1. (The foregoing components absent radiant grid 28 constitute a line burner in accord with the principles of the present invention, which is identified generally by reference character 20'.)

Referring now to FIGURES 1 and 2, distribution tube 22 is formed from sheet metal (aluminized sheet steel is satisfactory) into a generally diamondlike configuration defined by four side walls 36. As is best shown in FIG- URE 2, the opposed lateral edge portions of the sheet from which distribution tube 22 is formed are bent at angles to the two distribution tube walls 36 with which they are integral to form two parallel, spaced apart flanges 38 providing an outlet passage 40 from the interior to the exterior of the distribution tube. The preferred method of fabricating distribution tube 22 is described in the copending Fannon application mentioned above.

Orifice grid 24, through which the combustible fuelair mixture flows from distribution tube 22, is mounted in the outlet passage 40 of fuel-air mixture distribution tube 22 to prevent the flame from flashing back from the combustion zone through passage 40 to the interior of distribution tube 22. The illustrated orifice grid 24 is of the ribbon type (it is not critical that a ribbon type orifice be employed) and consists of embossed metallic ribbons which provide a number of small passages extending between and opening onto the opposed lateral edges of the assemblage of ribbons. The particular configuration of the individual ribbon is not critical in the present invention; and the length and total area of the lateral passages may be varied as desired for particular applications of this invention. It is necessary, however, that the lateral passages be sufliciently small in cross section and sufficiently long that flame cannot flash back through the passages from the combustion zone adjacent the outer face 26 of the orifice structure to the interior of distribution tube 22. In addition, the total area of the openings must be great enough that the combustible mixture will flow from distribution tube 22 to the combustion zone in sufli cient quantity to maintain the desired rate of combustion. As suitable orifice structures are disclosed in the above-mentioned copending Fannon application and as the construction of the orifice grid, by itself, is no part of the present invention, it is not believed necessary to disclose it in detail herein.

Orifice grid 24 is removably retained in outlet passage 40 between distribution tube flanges 38 by studs 42 and straps 44 (see FIGURE 1). Studs 42, which extend laterally through distribution tube flanges 38 at spaced intervals along the distribution tube, locate orifice grid 24 relative to the inner end 46 of the passage 40 betwen dis tribution tube flanges 38. Retainers 48, threaded on the ends of studs 42, clamp flanges 38 against orifice structure 24 to removably retain it in passage 40.

Straps 44, which prevent orifice structure 24 from dropping out of passage 40, are provided at the ends of distribution tube 22. They extend across passage 40 between the two distribution tube flanges 38 and are fixed to the flanges as by brazing.

The radiant grid 28, which is heated to incandescence by the combustible mixture flowing through orifice structure 24 and burning adjacent its outer face 26 and emits the radiant energy desired for space, article, or other heat-' ing in radiant energy applications of this invention, is preferably of the apertured construction disclosed in copending application No. 370,795 filed May 28, 1964, by Arthur C. W. Johnson. In the present invention, however, radiant grid 28 is made of a sheet of heat resistant metal such as Inconel or Hastaloy-X or a coated alloy and is bent into a horseshoe configuration providing a radiation emitting body 50 and inturned mounting flanges 52 extending toward each other from opposite sides of this body.

As best shown in FIGURES 2 and 3, the body 50 of radiant grid 28 is formed (by stamping or other process) into a configuration in which loops 54 are displaced from the plane of the sheet from which the grid is formed at regular intervals to form openings extending normal to the sheet through which the combustion products may pass from the combustion zone. As discussed in detail in copending application No. 370,795, this results in a grid which is a highly efiicient emitter of infrared radiation and which effectively protects the flame from air currents of sufficient strength to quench or snuff it out. In flanges 52, loops 54 are preferably flattened back into the plane of the flanges or are omitted to provide flat flanges which can be readily clamped between the members employed to attach grid 28 to distribution tube 22.

Referring now specifically to FIGURE 2, cars 56 are bent from grid body 50 at its ends. End plates 58 are fixed to the grid at its opposite ends by spot welding them to ears 56. End plates 58 support the open end of grid 28 and maintain the body of the grid in the desired shape. They also prevent air currents from disturbing the flame. If desired, an aperture 60 may be provided in one of the end plates 58 to facilitate lighting of the infrared generator, to accommodate a spark plug or flame sensor, and/ or to allow flame to travel from one radiant grid to the next in infrared generators having multiple radiants and adapted to be ignited at one end.

For radiant energy applications, radiant grid 28 is removably attached to the flanges 38 of fuel-air distribution tube 22 by cooperating pairs of inner and outer grid clips 62 and 64. A pair of clips 62 and 64 is employed on either side of radiant grid 28 at each of the studs 42, which extend through the clips. The retainers 48 threaded on studs 42 retain the grid clips and grid 28 in place.

In the assembled infrared generator 20 produced by adding radiant grid 28 to line burner 20', the space between each pair of clips 62 and 64 is slightly greater than the thickness of the associated flange 52. This permits longitudinal movement of radiant grid flanges 52 between the clips as the parts expand or contract due to temperature changes, but restrains the grid against appreciable transverse movement. This permits grid 28 to expand axially as its temperature increases, which prevents it from becoming distroted as it expands and contracts 1ongitudinally. Lateral expansion is accommodated by the horseshoe configuration of the radant grid so that the grid is almost entirely free from expansion and contraction induced distortions.

The reflectors 30 preferably employed in infrared generator 20 to form the infrared radiation emitted from grid 28 in a beam of the desired configuration and to project the beam in the desired direction or directions may be formed from sheets of aluminized steel or any other good reflector of infrared radiation. Retainers 66, threaded on the outer ends of studs 42, secure reflectors 30 on studs 42 against retainers 48 with the reflecting portions 68 of the two reflectors inclined outwardly relative to radiant grid 28. Reflectors 30 therefore concentrate the infrared radiation emitted from the grid and project it in a downwardly directed beam toward the area or onto the objects to be heated by infrared radiation.

The components of infrared generator 20 and the line burner 20 it embodies, as thus far described, may be identical to the corresponding components of the line burners and infrared generators described in the abovementioned copending Fannon application, to which reference may be had for a more detailed description of these components if desired. The line burners and infrared generator of the present invention illustrated in FIGURES 1 and 2 differ from those disclosed in the copending F annon application in that, as mentioned above, they include novel end brackets 32 and 34 for closing the ends of fuel-air mixture distribution tube 22 and for securely attaching the line burner 20' or infrared generator 20 to its supporting structure.

Referring now to FIGURE 4, sheet metal end bracket 32 has two integral legs 70 and 72, bent at right angles into an L-shaped configuration. With end bracket 32 assembled to distribution tube 22 (see FIGURE 1), bracket leg 70 is juxtaposed to and forms a closure for the open right-hand end of distribution tube 22; and bracket leg 72 extends along the top of distribution tube 22 in parallel, spaced relationship to the intersection 74 betwen the two integral upper side walls 36 of the distribution tube.

As best shown in FIGURES 2 and 4, two cage nuts 76 are welded in side-by-side relationship to the bottom side of bracket 32's mounting leg 72; and cooperating apertures 78 are formed in mounting leg 72 in alignment with the threaded central bores 80 of the cage nuts. By this novel arrangement, infrared generator 20 may be readily and securely attached to the diagrammatically illustrated supported frame 35 merely by threading the bolts 82 passing through the frame into cage nuts 76. As shown in FIG- URE 1, this clamps brackets 32s mounting leg 72 against supporting frame 35 to rigidly secure the infrared generator to the frame.

Referring now to FIGURES 1 and 4, an apperture 84 is formed in the closure forming leg 70 of bracket 32 to accommodate a combustible mixture supply conduit 86 which extends from the source of the combustible mixture (which is not shown, but may be, for example, a fuel-air mixer) into the interior of the fuel-air mixture distribution tube.

The end bracket 34 employed at the end of fuel-air mixture distribution tube 22 opposite end bracket 32 is identical to end bracket 32 except that there is no combustible mixture supply conduit at this end of distribution tube 22; and, therefore, no aperture 84 in bracket 34.

End brackets 32 and 34 are attached to fuel-air mixture distribution tube 22 by angle clamps 88 which are best illustrated in FIGURE 3 and which are fixed in pairs to each end of fuel-air mixture distribution tube 22. Referring now to the latter figure, each of the angle clamps 88 includes a clamping leg 90 and a base leg 92 bent, midway between its ends, to form two base portions 94 and 96 adapted to abut adjacent upper and lower side wall members 36 of distribution tube 22.

Angle clamps 88 are fixed to distribution tube 22 by spot welding the two base portions 94 and 96 to side wall members 36 of fuel-air mixture distribution tube 22. As shown in FIGURE 2, the two angle clamps 88 at each end of fuel-air mixture distribution tube 22 are aligned transversely of the distribution tube so that the outer faces 98 of the clamping legs 90 of the two angle clamps at each end of the distribution tube lie in the same transverse plane.

The mounting legs 72 of end brackets 32 and 34 are fixed to the clamping legs 90 of the angle clamps at each end of fuel-air mixture distribution tube 22 by bolts 100 which extend through aligned apertures 102 in the end brackets and 104 in the angle clamps. Nuts 106, threaded on bolts 100, clamp end brackets 32 and 34 against the angle clamps.

Referring now to FIGURE 1, to prevent the combustible mixture from leaking through the end of fuel-air mixture distribution tube 22 between it and end brackets 32 and 34, circular gaskets 108 and 110 are assembled between the closure forming legs 70 of end brackets 32 and 34 and the associated ends of distribution tube 22. When bolts 100 are tightened, gaskets 108 and 110 are compressed and form a gas tight seal between the ends of the distribution tube and the associated closure forming legs 70 of the two end brackets.

A central aperture 112 is formed in gasket 108 to accommodate combustible mixture supply conduit 86, but the two gaskets 108 and 110 may otherwise be identical.

Many modifications of the exemplary line burner infrared generator embodiment just described may, of course, be made within the scope of the present invention. For example, with only slight physical modifications, angle clamps and endbrackets as described above may be employed with fuel-air distribution tubes of various cross sectional configurations.

Another exemplary application of the principles of the present invention is illustrated in the infrared generator 114 depicted in FIGURE 5. Infrared generator 114, which embodies a line burner 114', is identical to the infrared generator 20 as described above except that infrared generator 114 is much longer than infrared generator 20; and, therefore, its radiant grid 116 is formed in three independent sections 118, 120, and 122 disposed in end-to-end relationship longitudinally of fuel-air mixture distribution tube 124, As discussed in copending Fannon application 395,839, mentioned above, this prevents distortion of the radiant grid due to expansion and contraction as infrared generator 114 heats up and cools off. Infrared generators and line burners of the type shown in FIGURE may readily be provided with end brackets and angle clamps of the type described above (the end bracket, angle clamps, and other components of infrared generator 114 which are identical to the corresponding components of infrared generator 20 are identified by the same reference characters).

In many respects, the infrared generator 126 illustrated in FIGURE 6 (and the line burner 126 it encompasses) are identical to the infrared generator 20 and line burner 20 of FIGURE 1. To the extent that the components of these two embodiments are alike, they will be identified by the same reference characters.

Infrared generator 126 differs from infrared generator 20 primarily in the nature of the straps 128 employed to support orifice grid 24, in the one-piece clips 130 utilized to support radiant grid 28, and in the construction of reflectors 132. As shown in FIGURES and 11, the radiant grid supporting straps 128 employed in infrared generator 126 (and line burner 126) have a generally U-shaped configuration provided by two parallel, spaced apart side members 134 and 136 and an integral, connecting web 138 which is substantially narrower than the side members.

As shown in FIGURE 6, each orifice grid supporting strap 128 is assembled with its side members 134 and 136 adjacent the flanges 38 of fuel-air mixture distribution tube 22 by one of the studs 42, which extends through aligned apertures 140 in the strap members 134 and 136. With strap 128 thus assembled to fuel-air mixture distribution tube 22, web 138 abuts and supports the outer end 26 of orifice grid 24, preventing it from dropping out from between distribution tube flanges 38, but permitting it to be slid lengthwise of the distribution tube to remove it from infrared generator 126.

Generally two orifice grid supporting straps 128 will be employed for each infrared generator 126, one near each end of fuel-air mixture distribution tube 22. However, for longer line burners and infrared generators, three or even more straps 128 may be employed.

The use of the novel orifice grid supporting straps 128 just described eliminates the brazing operation necessary to attach straps of the type shown at 44 in FIGURE 1. This assembly operation is replaced with the much simpler and more expeditiously accomplished step of merely sliding straps 128 over distribution tube flanges 38 and aligning apertures in the straps with those in flanges 38. Therefore, by employing straps 128, one manufacturing operation is replaced by another which is much more simple and expeditiously accomplished, effecting a significant reduction in manufacturing cost.

Referring now to FIGURES 7, 8, and 9, the novel clips 130 employed in infrared generator 126 to support radiant grid 28 are formed of temperature resistant sheet metal and have a main body portion 142 and three triangular legs 144, 146, and 148, which extend at right angles from clip main body portion 142. As best shown in FIGURES 6, 7, and 8, triangular legs 144 and 148 lie in the same plane; and leg 146 lies in a plane which is below legs 144 and 148 a distance slightly greater than the thickness of radiant grid flanges 52.

Radiant grid supporting clips 130 are fixed to the fuelair distribution tube 22 of infrared generator 126 by studs 42, which extend through apertures 150 in the main body portion 142 of the clip, and retainers 48, which clamp clips 130 against the flanges 38 of distribution tube 22.

As is best shown in FIGURES 6 and 12, with infrared generator 126 assembled, the two triangular legs 144 and 148 of each clip 130 engage the upper surface of the associated flange 52 of radiant grid 28; and the central clip leg 146, the lower side of the associated flange, thus supporting radiant grid 28 from fuel-air mixture distribution tube 22. The distance between the two sets of grid clip legs is preferably slightly greater than the thickness of flanges 52. This permits longitudinal movement of flanges 52 between the legs of the clips as the parts expand and contract due to temperature changes, but restrains flanges 52 and the body of grid 28 from appreciable transverse movement. This permits grid 28 to expand axially as the temperature increases, which prevents it from becoming distorted as it expands and contracts longitudinally. As in the embodiment of FIGURE 1, lateral expansion is accommodated by the horseshoe configuration of the grid.

Replacement of the cooperating clips 62 and 64 of the embodiment of FIGURE 1 with the single clip 130 discussed above makes it possible to produce a Fannon type infrared generator at a significantly lower cost because both the number of different types of components which it is necessary to fabricate and the number of assembly steps are reduced. In addition, radiant grid supporting clips 130 can be assembled to radiant grid 28 and to fuel-air mixture distribution tube 22 after the construction of these components is completed. This makes assembly of infrared generator 126 easier than that of an infrared generator employing clips of the type illustrated in FIGURES 1 and 2 as, when the latter are used, the clips must be attached to grid 28 before end plates 58 are attached to the radiant grid body 50 and the fabrication of the radiant grid then completed.

In most instances, two pairs of grid clips 130, one near each end of infrared generator 126, will be sufficient to securely fix radiant grid 28 in place. For very long burners, however, additional pairs of grid clips may be employed intermediate the ends of the infrared generator, i-f desired.

Referring now to FIGURES 6 and 13, each of the two reflectors 132 of infrared generator 126 consists of a first reflecting member 152 and a second reflecting member 154 connected by Z-shaped mounting straps 156 by which reflectors 132 are mounted on fuel-air mixture distribution tube 22.

As shown in FIGURES 6 and 13, reflective members 152 are of generally rectangular configuration and are fixed, as by brazing, to an upwardly inclined intermediate leg 158 of each mounting strap 156.

Reflective members 154 have a V-shaped cross sectional configuration, defined by a first upwardly inclined portion 160 and a second, integral, generally vertically extending portion 162. Reflective members'154 are fixed to mounting straps 156 by brazing or otherwise attaching their upper portion 160 to downwardly extending legs 164 of straps 156.

A third leg 166 of each mounting strap 156 extends vertically through -a rectangular slot 168 cut in each reflective member 152. Studs 42 extend through apertures 170 in mounting strap legs 166; and the mounting straps are retained on studs 42 by retainers 66 which clamp legs 166 against retainers 48. Generally two straps 156 are used for each reflector 132, one adjacent each end of the infrared generator. However, additional straps can be employed at intermediate points, if desired.

As shown in FIGURES 6 and 13, the novel reflector arrangement just described provides a passage 172 between reflective members 152 and 154 extending the length of infrared generator 126, through which combustion products may escape after passing from the combustion zone adjacent the outer end 26 of orifice grid 24 through radiant grid 28. This facilitates the escape of combustion gases from the combustion zone, which is important for satisfactory operation in many applications for which infrared generators of the type to which the present invention relates are adapted.

Reflectors 132 need not necessarily have the particular configuration depicted in FIGURE 6. On the contrary, the configuration of the reflective members and the Z- shaped mounting brackets 156 may be varied to form the radiant energy emitted from radiant grid 28 into a beam of the configuration desired for a particular application.

Reflective members 152 and 154, as in the embodiment of FIGURES 1 and 2, may be fabricated of aluminized steel or any other suitable temperature resistant reflective materials.

The infrared generator 173 of the present invention illustrated in FIGURES 14 and 15 is, in most respects, identical to the infrared generator embodiments described clips 174 end brackets 17 8, which are identical to the end brackets 32 and 34 described previously (the cage nuts are omitted from end brackets 178 for the sake of clarity), except that end brackets 178 have a closure forming leg 180 which extends well below the outer end or surface 26 of orifice grid 24. A rectangular aperture or slot 182 is formed in each of the end brackets 178. As shown in FIGURE 14, orifice grid 24 extends through apertures 182 so that the elongated closure forming legs 180 assist in supporting orifice grid 24 in the embodiment of the present invention illustrated in FIGURES 14 and 15.

As in the embodiment described previously, one combination clip 174 at each end of infrared generator 173 will, in most cases, be suflicient. However, if desired, additional clips at intermediate points may be employed for longer infrared generators.

From the foregoing, it will be apparent that the use of combination clips 174 effects even further reductions in manufacturing costs in comparison to the innovations described above in conjunction with the embodiments of FIGURES l and 6. Specifically, combination clip 174 reduces (from three in the case of FIGURE 1 or two in the case of the embodiment of FIGURE 6) to one the number of infrared generator components required to support orifice grid 24 and radiant grid 28. Therefore, this novel combination clip even futher reduces the number of infrared generator components which it is necessary to fabricate and the number of assembly operations.

The principles of the present invention have been developed to a large extent by relating them to Fannon type infrared generators. However, many of the novel features of the present invention such as end brackets 32 and 34 and 178 and orifice grid supporting strap 128 are equally applicable to the Fannon type line burners incorporated in the illustrated infrared generators and adapted to be used as such by assembling the illustrated devices without radiant grid 28 and its supporting components. Such utilization of these novel line burner components are, there fore, to be understood as being within the scope of the present invention except as specifically excluded from the appended claims.

It will also be apparent to those skilled in the art to which the present invention relates that many modifica tions of the particular components disclosed above including many of those disclosed in copending Fannon application No. 395,839 can readily be made. Such modifications are also fully intended to be covered by the appended claims except as specifically excluded, the foregoing detailed description of exemplary embodiments of previously. The same reference characters will, therefore,

be employed to identify components of infrared generator 173 which are identical to those of infrared generators 20 and 126.

Infrared generator 173 diflers from those described previously in that the orifice grid supporting straps 44 and radiant grid supporting clips 62 and 64 of the embodiment of FIGURE 1 (or the orifice grid supporting straps 128 and radiant grid supporting clips 130 of the embodiment of FIGURE 6) are all replaced with a single combination clip 174 adapted to support both orifice grid 24 and radiant grid 28.

As shown in FIGURES l5 and 16, clips 174 are identical to the clips 130 employed in infrared generator 126 except that a fourth triangular leg 176 is bent from each clip 174 in the plane of upper legs 144 and 148 and in the opposite direction therefrom. As shown in the figures just mentioned, with infrared generator 173 assembled, clip legs 176 underlie and support orifice grid 24 in the same manner as the orifice grid supporting straps 44 and 128 described previously.

There are also preferably employed with combination this invention being intended to be merely illustrative and not limiting.

From the foregoing, it will be apparent that line burners and infrared generators constructed in accord with the principles of the present invention possess the advantages of those disclosed in copending Fannon application No. 395,839 mentioned above. In addition, burners and infrared generators constructed in accord with the principles of the present invention are even more easily manufactured than those disclosed in the forementioned copending application because of the novel end brackets described above which eliminate brazing operations required to attach the end closures to the distribution tubes of the line burners and infrared generators of the copending applicatron. Also, these novel end brackets provide a simple and effective arrangement for securely attaching line burners and infrared generators to their supporting st-ructue. The gasketed end brackets also effectively eliminate leakage of the combustible mixture from the ends of the distribution tube and the necessity of brazing the combustible mixture supply conduit to the tube as the gasket provides an effective gas tight seal around the conduit. Even further significant gains in reduction of manufacturing costs and better operation are obtained by the various novel orifice and radiant grid supporting components and the novel modified reflectors described above.

In conjunction with the foregoing, it is also important to note that all of the components of the line burners and infrared generators of the present invention which differ from those disclosed in copending Fannon application No. 395,839 are of sheet metal construction or are common fasteners, which minimizes manufacturing costs. So does the extensive use of bolts, screws, and other threaded type fasteners, which materially facilitates the assembly of line burners and infrared generators embodying the principles of the present invention by mass production techniques.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In a burner of the combustion type:

(a) an elongated fuel-air mixture distribution tube;

(b) clamping angles at the ends of said tube, each clamping angle having a first leg fixed to said distribution tube and a second leg extending at right angles to the first leg and to the longitudinal axis of the distribution tube with the second legs of the angles at each end of said tube aligned transversely of said tube; and

(c) a support for said burner removably fixed to the second legs of the clamping angles at each end of said distribution tube, said support being a separate member from the clamping angles to which it is fixed and having a leg spanning and forming a closure for the end of the distribution tube at which it is located, said leg abutting said tube end and the second legs of the clamping angles thereadjacent.

2. In a burner of the line type:

(a) an elongated fuel-air mixture distribution tube;

(b) clamping angles substantially equally spaced around the periphery of said tube at the opposite ends thereof, each clamping angle having a first leg immovably fixed to said distribution tube and a second leg extending at right angles thereto with the second legs of the angles at each end of said tube aligned transversely of the tube; and

(c) an end bracket at at least one end of said tube,

said end bracketbeing separable from said clamping angles and includin a first leg removably fixed to the second legs of t e clamping angles at the associated end of said distribution tube, said first leg spanning and forming a closure for the end of the distribution tube at which the bracket is located, a second leg integral with said first leg, and means fixed to said second leg by which said bracket may be attached to mounting structure to support said burner therefrom.

3. The burner of claim 2, wherein said attaching means comprising internally threaded retainers fixed to the second legs of said end brackets.

4. The burner of claim 3, wherein the second legs of the two end brackets extend toward each other in generally parallel spaced relation along said distribution tube, said retainers are cage nuts fixed to the surfaces of said second legs adjacent said distribution tubes and apertures communicating with the threaded bores of said nuts are formed in said second legs.

5. The burner of claim 2, wherein said distribution tube has four wall portions in a diamondlike configuration and the first leg of each of said clamping angles has two angularly disposed portions adapted to abut and be fixed to two adjacent wall portions of said tube.

6. An infrared generator of the combustion type comprising a line burner as defined in claim 2 and a radiant grid for converting the energy liberated by combustion of a fuel-air mixture in said burner to infrared radiation.

7. An infrared generator of the combustion type, comprising:

(a) a line burner including an elongated fuel-air mixture distribution tube;

(b) a radiant grid for converting energy liberated by combustion in said burner to infrared radiation; and

(c) reflectors on opposite sides of and spaced from said radiant grid, each of said reflectors comprising first and second reflective members and mounting brackets at the opposite ends thereof, each of said brackets having three legs, said reflective members being fixed to the first and second legs of said brackets, respectively, in spaced apart relationship to provide a passage therebetween for the escape of combustion products, the third leg of each of said mounting brackets being fixed to said distribution tube.

8. In an infrared generator of the combustion type:

(a) an elongated fuel-air mixture distribution tube 22 having opposed flanges 38 forming a passage communicating between the interior and exterior of said tube and extending the length thereof;

(b) an orifice grid 24 disposed between said flanges;

(c) a radiant grid 28 extending the length of said tube and having mounting flanges 52 on the sides thereof;

((1) a stud 42 extending between and through said flanges at each end of said tube; and

(e) clips 174 supported on each of said studs, one adjacent each of said tube flanges, each of said clips having a plurality of projections 144, 146, 148, 176, different ones of said projections 144, 146, 148 being adapted to abut opposite sides of said grid mounting flanges for fixing said radiant grid to said distribution tube and at least one of said projections 176 being disposed to abut said orifice grid for retaining said orifice grid between said tube flanges.

9. The infrared generator of claim 8, together with end brackets 178 having closure forming portions 180 extending across the ends of said distribution tube, said closure forming portions having apertures 182 therethrough and the ends of said orifice grid 24 extending through said apertures whereby it is supported by said end brackets.

10. In a burner of the line type:

(a) a hollow elongated fuel-air mixture distribution tube open at its ends;

(b) end brackets fixed to said distribution tubes at the ends thereof, said brackets each including a first portion forming a closure for the end of the distribution tube at which the bracket is located, said first portion abutting and spanning the distribution tube end, and a second portion integral with said first portion comprising means by which said bracket may be attached to mounting structure to support said burner therefrom;

(c) clamping members fixed to said distribution tubes adjacent the closure forming portions of said brackets; and

(d) fastener means extending through each said bracket and the adjacent clamping member and biasing the closure forming leg toward the end of the distribution tube abutted thereby to seal the joint between the closure forming leg and the end of the tube.

11. An infrared generator of the combustion type,

comprising:

(a) a line burner including an elongated fuel-air mixture distribution tube;

(b) a radiant grid for converting energy liberated by combustion in said burner to infrared radiation; and

(c) reflectors on opposite sides of and spaced from 13 14 said radiant grid, each of said reflectors comprising 2,575,514 11/1951 Furczyk 158- 113 at least two spaced apart supporting members fixed 2,652,107 9/ 1953 Hughes 158104 X to said distribution tube and a pair of reflective 2,720,258 10/ 1955 Brodbeck et al 15 8-113 members with a passage therebetween extending sub- 2,867,207 l/ 1959 F ulmer. stantially the length thereof through which com- 5 2,884,998 5/ 1959 Taylor 158116 bustion gases can escape, said reflective members be- 3,129,749 4/ 1964 Honger 158--112 X ing fixed to said spaced apart members and extend- 3,132,642 5/1964 Fingland. ing parallel to said distribution tube. 3,139,881 7/ 1964 Fannon 12692 References Cited 10 FOREIGN PATENTS UNITED STATES PATENTS 945,715 12/1948 France. 1,189,094 6/1916 Goodwin et a1. 450,550 7/1936 Great i i 2,162,374 6/1939 Chambers 15s 99 842,596 7/1960' Brltam- 2,288,898 7/1942 French 158-104X 1 I 2 39 39 4 194 bb 15 11 X 5 FREDERICK L. MATTESON, JR., Przmary Examiner. 

1. IN A BURNER OF THE COMBUSTION TYPE: (A) AN ELONGATED FUEL-AIR MIXTURE DISTRIUBTION TUBE; (B) CLAMPING ANGLES AT THE ENDS OF SID TUBE, EACH CLAMPING ANGLE HAVING A FIRST LEG FIXED TO SAID DISTRIBUTION TUBE AND A SECOND LEG EXTENDING AT RIGHT ANGLES TO THE FIRST LEG AND TO THE LONGITUDINAL AXIS OF THE DISTRIUBTION TUBE WITH THE SECOND LEGS OF THE ANGLES AT EACH END OF SAID TUBE ALIGNED TRANSVERSELY OF SAID TUBE; AND 